Rousey will put that record on the line and look to make it a lucky 13 in Melbourne on Sunday, facing boxing champion Holly Holm at UFC193. The event at Etihad Stadium is expected to be the most-attended fight in the history of the UFC, with Rousey's star shooting to astronomical heights in recent times.

The reason why she's suddenly the biggest thing in combat sports? It's hard to pin down to one reason. Maybe it is her brutal takedowns, including the record-setting 14 seconds she took to beat Cat Zingano in February, beating the 16 seconds it took for her to knock out Alexis Davis in July 2014.

Maybe it's that she consistently gets the job done quickly -- her last three fights have a combined running time of just 64 seconds.

Maybe it's her decrying of "do nothing bitches," which has become a catchphrase and ethos around the world.

Or maybe it's just that she's simply one of the most gifted, incredible, brutal and focused athletes in the world right now.

No matter the reason, Rousey is a phenomenon all of her own, and Sunday's fight will only add to her already trailblazing legacy.